The invention relates to apparatus and a method of printing on edible substrates, and more particular but not exclusively, to apparatus and a method of printing polychromatic or monochromatic images on edible substrates using food dies or edible inks.
Throughout this specification and in the claims annexed hereto to the term xe2x80x9cimagexe2x80x9d is to be taken to refer to any polychromatic or monochromatic design, picture, text pattern or the like to be produced by the apparatus of the invention.
Decorated cakes are well known and have been decorated for many years by hand and examples of methods currently in use include hand printing of a design, spraying a food colorant through a stencil, cutting out shapes from soft icing or marzipan, piping designs (with molten chocolate or soft icing), applying plastic or other types of novelty directly to the surface of the cake, silk screening images onto plaques of sugar or water fixed to the cake.
Most celebration cakes are decorated by hand and rely on the skill and dexterity of the operative to achieve high quality results. These types of decorated cakes are, however, expensive and time consuming to produce because of the skilled labour involved moreover, no equipment is known to exist to produce a commercially viable product by hand with fine detail together with a multiplicity of colours or fine shading.
Attempts have been made to automate the decoration of cakes and other edible substrates. One such attempt is to be found in U.S. Pat. No. 4,910,661 which describes a method and apparatus for capturing live video images which are displayed on a monitor, the images then being mixed with textual matter and other artwork. After editing, the displayed video image may be reproduced on a cake by means of applicators such as airbrushes for applying liquid food colorants and dispensers for applying icing or decorating gel to the cake carried on an XY table moved systematically of the top of the cake.
One aspect of the invention provides apparatus for printing an image on an edible substrate. The apparatus comprises a print head assembly including one or more containers for holding liquid food colorants, and a support for holding an edible substrate adjacent the print head assembly. The support is adjustable such that a surface of the support upon which an edible substrate is placed may be moved vertically towards and away from the print head assembly. The support and print head assembly are also movable laterally, relative to one another. A controller is provided for controlling the print head assembly with printing instructions and for causing the relative lateral movement. In this way, the colorants are ejected on to the edible substrate at appropriate locations to print the desired image.
Thus, the invention permits both relative lateral movement of the print head assembly and the edible substrate (e.g., in both the X and Y directions), and vertical movement of the print head assembly relative to the substrate, e.g., in the Z direction. By providing relative vertical movement, the position of the surface being printed upon may be adjusted in view of different thicknesses of the edible substrates which might be processed in the apparatus of the invention.
In one particular aspect, the support for the edible substrate may have an upper plate supported above a carrier by an adjuster operable to enable the spacing of the upper plate from the carrier to be adjusted.
The support may comprise a lower plate which in use rests on the corner, the adjusts being operable to the way of the spacing of the upper and lower plates.
The adjuster may advantageously comprise a scissors mechanism acting between the upper and lower plates of the support or between the upper plate and the carrier and may include two pairs of pivotally connected arms, a first end of one arm from each pair of arms is pivotally mounted on a member fixed to the lower support plate and the other ends of which support a rotatable member bearing against the upper support plate. Further, a first end of the other arm in each pair is pivotally coupled to a member movable relative to the lower support plate or carrier and the other ends of which support a rotatable member bearing on the lower support plate.
The pivotal connections of the first end of said one arm of each pair of arms may be fixed to a cross member which is fixed to and carried on the lower support plate and the pivotal connection of the first end of the other arm of each pair of arms is fixed to a second cross member. Further, the second cross member may have a threaded aperture through which a set screw is received to bear against the first cross member. In this way, adjustment of the screw in the threaded aperture adjusts the spacing of the second and first cross members.
Relative lateral movement of the print head assembly and the support may be effected by a pair of stepping motors. For example, a first of the stepping motors may be arranged to drive the print head assembly along a carriageway in a first (X) direction relative to the support for the edible substrate, and the second of the stepping motors may be arranged to drive the support, with the edible substrate in a second (Y) direction substantially normal to the first.
Power may be applied to the second stepping motor only when it is desired to move said support.
The apparatus may further include means for controlling use of copyright images. For example, the apparatus may include means adapted to monitor for a copyright holder the number of times a copyright image is printed and may further be adapted to limit the ability to recolor copyright images.
In a second aspect the invention provides a method for printing an image on an edible substrate. According to the method, the edible substrate is placed on a support. A print head assembly including one or more containers that hold a liquid food colorant is placed adjacent and above the edible food substrate, the position of the support is vertically adjusted such that the surface of the edible substrate that is to be printed upon is at a desired distance from the print head assembly. Movement of the support and print head assembly laterally relative to one another are controlled while operating the print head assembly to eject the food colorant on to the substrate based on printing instructions to print the desired image on the edible substrate.
With advantage the method may further include the step of controlling copyright images in the printing process. In this way, a user may be prevented from printing certain copyright imaged.
The method may include monitoring the number of times a copyright image is printed and/or permitting the ability to recolor images which are copyright.